Process for producing soybean protein material

ABSTRACT

There is disclosed a process for producing a soybean protein material which comprises the steps of: hydrolyzing soybean protein with a protease in an aqueous system to an extent of hydrolysis of 5 to 20; if necessary, emulsifying an oil-and-fat ingredient with soybean protein in an amount of 5 to 50 parts by weight per 100 parts by weight of the soybean protein before or after the hydrolysis step; drying the resultant emulsified mixture; and, optionally, a step for dispersing an emulsifier being provided at any stage after emulsification with the oil-and-fat ingredient. The soybean protein material thus obtained has taste, color and water-dispersibility suitable for a pickling solution having a high concentration and thick drinking food such as soup with less foaming property.

FIELD OF THE INVENTION

The present invention relates to a process for producing a soybeanprotein material, especially, a soybean protein powder having goodwater-dispersibility. It also relates to a process for producing asoybean protein powder having low solution viscosity and gel-formingability upon heating. The soybean protein powder of the presentinvention is a soybean protein material suitable for using thickdrinking food such as soup, pickling solutions and the like.

PRIOR ART

JP-B 48-24262 discloses a soybean protein product obtained byhydrolyzing soybean protein with a specific enzyme and spray-drying thehydrolyzed product and there is described that fats and oils,saccharides, vitamins and the like which have been pasteurized orsterilized separately can be added thereto before or after heattreatment. However, the product is a kind of oligopeptides having a lowmolecular weight such as that having a hydrolysis degree of about 24 ofAPL (average peptide length). Therefore, the product does not havegel-forming ability with sufficient water-solubility andwhipping-ability and is unsuitable for thick drinking food and picklingsolutions due to foaming.

In addition, JP-A 58-180796, a catalog of Lucas Meyer Corp. and the liketeach methods for coating soybean protein with lecithin. However, theyare not a method for dispersing soybean protein.

Further, JP-A 5-328939 discloses the use of a enzymatically hydrolyzedproduct of soybean protein as a pickling solution. JP-A 6-46799discloses the use of a hydrolyzed product of soybean protein with anesterase as a pickling solution. However, any fats and oils are not usedtogether with soybean protein and soybean protein is used alone.

On the other hand, when a past of a soybean protein powder (water-addedand kneaded product) is heated, it forms a gel having good properties.Then, for example, a soybean protein powder is incorporated into amixture of raw materials for meat products, or raw materials for meatproducts is soaked in a soybean protein solution. However, since aconventional soybean protein solution has high viscosity, there is sucha problem that, when it is used as a solution for soaking, a largeamount of a soybean protein solution cannot be incorporated into rawmaterials of meat products.

OBJECTS OF THE INVENTION

As indicated above, mere enzymatic hydrolysis of a soybean proteinisolate causes lowering of gel-forming ability and increase in foamingand therefore, for preparation of thick drinking food such as soup orpickling solutions, there is a problem of workability. The main objectof the present invention is to provide a soybean protein material havinggood flavor and color tone which has high salting-in property in so faras it has gel-forming ability satisfactory for a pickling solution,which is readily dispersed in water upon preparation of a picklingsolution, which has less foaming ability so that a pickling solutionhaving a high concentration can be prepared (i.e., with low viscosity),and which does not form a pool of a pickling solution after injection ofthe solution into ham.

SUMMARY OF THE INVENTION

In order to attain the above objects, the present inventors have studiedintensively. As a result, it has been found that a soybean proteinmaterial, wherein the above problem in conventional soybean proteinmaterials is improved, can be obtained by enzymatically hydrolyzingsoybean protein to a certain extent, and by emulsifying the hydrolyzedsoybean protein with a oil-and-fat ingredient in an aqueous system and,upon drying, dispersing an emulsifier in the resultant emulsifiedmixture and drying. Thus, the present invention has been completed.

That is, the first aspect of the present invention is a process forproducing a soybean protein material which comprises the steps ofhydrolyzing soybean protein with a protease in an aqueous system to ahydrolysis degree of 5 to 20; emulsifying an oil-and-fat ingredient withthe soybean protein in an amount of 5 to 50 parts by weight per 100parts by weight of the soybean protein before or after the hydrolysisstep; and drying the resultant emulsified mixture. Optionally, afteremulsification, a step for addition of an emulsifier to the soybeanprotein can be provided before or after the drying step.

The second aspect of the present invention is a process for producing asoybean protein material which comprises the steps of: hydrolyzingsoybean protein with a protease in an aqueous system to a hydrolysisdegree of 5 to 20; adding an emulsifier to the soybean protein anddrying the resultant. The step for addition of the emulsifier can beconducted before or after the drying step.

In any of first and second aspects of the present invention, when theemulsifier is used, preferably, the emulsifier is present in anemulsified and dispersed state in an amount of 0.1 to 3 parts by weightper 100 parts by weight of solids content of the soybean protein.

The soybean protein material obtained by the process of the presentinvention is suitable for a pickling solution in addition to thickdrinking food such as soup and the like.

DETAILED EXPLANATION OF THE INVENTION

The soybean protein to be used in the present invention is notspecifically limited. However, as the soybean protein, suitably, thereare soybean protein extracted from soybeans with water, soybean proteinisolates, soybean protein concentrates and the like. Among them,normally, a soybean protein isolate is produced by extracting soybeanprotein from defatted soybeans with water and precipitating soybeanprotein at isoelectric point. A soybean concentrate contains an "okara(insoluble residue from soymilk production)" ingredient because it isnot removed upon extraction with water.

The protease used in the present invention may be any proteasesoriginated from vegetable (papain, buromelain, ficin, etc.), originatedfrom animal (pepsin, trypsin, chymotoripsin, etc.), originated frommicroorganisms (Protin, Alkalase, Thermoase, etc). In addition,endo-proteases and a combination of endo- and exo-proteases and the likecan be used. Any of acid proteases, neutral proteases, alkalineproteases and the like can be used. However, neutral proteases arepreferred because neutralization is not required in the productionsteps.

A method for the enzymatic hydrolysis is not specifically limited and ahydrolysis temperature range and a pH range can be selected from theactive temperature range and the active pH range of a particularprotease to be used.

Although the amount of a protease varies according to the activity of aparticular protease, normally, 0.05 to 5 parts by weight, practically0.02 to 2 parts by weight of the protease is used per 100 parts of thesoybean protein.

In addition, a hydrolysis degree of the soybean protein is adjusted to 5to 20, preferably 6 to 15, wherein the hydrolysis degree is a ratio (%)of 0.22M trichloroacetic acid-soluble protein to the total proteins.

When the hydrolysis degree is less than 5%, increase in solutionviscosity due to emulsification with the oil-and-fat ingredient asdescribed hereinafter and denaturation of proteins due to decrease inmoisture evaporation upon drying are liable to be caused. Thereby,salting-in property is liable to be lowered and viscosity becomes high,which results in difficulties in production of thick pickling solutionsand thick drinking food such as soup. When the hydrolysis degree is morethan 20, gel-forming ability is lowered and foaming is liable to causein production of pickling solutions. This is not suitable.

Thus, according to the present invention, when the hydrolysis degree isin the range of 5 to 20, a pickling solution having a high concentrationcan be obtained by using the soybean protein material of the presentinvention because viscosity can be lowered without deterioration ofsalting-in property and sufficient gel-forming ability of the picklingsolution can be provided. And yet, as described hereinafter, thepickling solution having less foaming property can be obtained byemulsifying the soybean protein with the oil-and-fat ingredient ordispersing an emulsifier therein, synergistically.

Furthermore, when the hydrolysis degree is maintained within such range,a peculiar flavor of soybean due to hydrolysis is not produced and, asdescribed hereinafter, a pleasant flavor can be obtained by using theoil-and-fat ingredient together.

At the end of hydrolysis, heating can be carried out for inactivation ofthe enzyme as well as pasteurization or sterilization. Usually, heatingat 80° to 160° C. for 3 seconds to 60 minutes is suitable. Forindustrial production, heating at 130° to 150° C. for 7 to 60 secondscan be carried out by using a high-temperature-short-time sterilizer orthe like.

According to the present invention, problems of soybean proteins causednot only by enzymatic hydrolysis but also by using soybean proteinswhich violently foam and have a peculiar soybean flavor, dark color andthe like can be solved by emulsifying the soybean protein with theoil-and-fat ingredient and/or an emulsifier.

As the oil-and-fat ingredient, according to particular use, there can beused vegetable fats and oils such as palm oil, coconut oil, soybean oil,cotton seed oil, corn oil, safflower oil, rice bran oil and the like,animal fats and oils such as beef fat, lard, fish oils, other animalfats and the like, fats and oils from microorganisms such as yeast,their fractionated, interesterified derivatives and the like. Theoperation for injecting a pickling solution into ham is carried out at alow temperature and, when the oil-and-fat ingredient to be used is solidor plastic at a low temperature (usually about 5° C.), increase inviscosity of a pickling solution or a pool of a pickling solution in thetexture of ham may be caused. Therefore, the oil-and-fat ingredient tobe used is preferably liquid at ordinary temperature. In particular, theoil-and-fat ingredient is preferably liquid at about 5° C. In thickdrinking food such as soup and the like, semi-solid fats can be used.

The ratio of the enzymatic hydrolyzed soybean protein or soybean proteinand the oil-and-fat ingredient is suitably 5 to 50 parts by weight,preferably 10 to 25 parts by weight of the oil-and-fat ingredient per100 parts by weight of the enzymatic hydrolyzed soybean protein orsoybean protein. When the amount of the oil-and-fat ingredient is toosmall, foaming upon preparation of a pickling solution is hardlyinhibited. In addition, color of a tissue of ham injected with such apickling solution tends to become dark and the peculiar soybean flavoralso tends to be remained. On the other hand, when the amount of theoil-and-fat ingredient is too large, a white stripe pattern tends toform in a tissue of ham injected with such a pickling solution and it isundesirable. If the above ratio of the present invention is employed,the ham obtained has a bright colored tissue and pleasant taste, whichresults in high quality.

According to the present invention, the emulsion thus obtained or adried material of the emulsion itself can be used as a raw material ofthick drinking food such as soup and pickling solutions. However,preferably, an emulsifier is further dispersed therein. Even if anemulsifier is not used, a pickling solution having less foamingproperty, lower viscosity and more bright color in comparison with aconventional soybean protein can be obtained by the above enzymatichydrolysis and emulsification with the oil-and-fat ingredient. However,when such an emulsifier is used together, water-dispersibility uponpreparing a pickling solution can further be improved to increaseworkability and quality of ham injected with the pickling solution canbe improved.

As the emulsifier used in the present invention, there can be usedglycerin fatty acid esters, sucrose fatty acid esters, sorbitan fattyacid esters, propylene glycol fatty acid esters, polyglycerol fatty acidesters, polyglycerol condensed licynolate fatty acid ester, lecithins(inclusive enzymatic modified lecithins such as lysolecithin) and thelike. They can be used alone or in combination thereof. Theirhydrophilic or lipophilic nature is not specifically limited.

The emulsifier is suitably used in an amount of 0.1 to 3 parts byweight, preferably 0.2 to 2 parts by weight per 100 parts by weight ofsoybean protein solids in the emulsions. When the amount of theemulsifier is too small, only a litter effect on improvement ofwater-dispersibility upon preparation of a pickling solution andinhibition of foaming is expected. On the other hand., when the amountof the emulsifier is too much, an emulsifier flavor becomes strong andthis is undesired. In case of thick drinking food such as soup, thesituation is the same. In the present invention, the emulsifier is usednot only for emulsification of the soybean protein, the oil-and-fatingredient and water but also for other objectives such as inhibition offoaming and the like. In particular, preferably, the emulsifier is usedin the already prepared emulsion mixture of the soybean protein and theoil-and-fat ingredient. That is, the emulsifier is dispersed in theemulsion mixture of the soybean protein and the oil-and-fat ingredientand then the resulting dispersion is dried to obtain an emulsifiedsoybean protein powder, or the emulsifier is added after drying. Whenthe emulsifier is emulsified with the already prepared emulsion mixtureand is completely homogenized, only a little effect on inhibition offoaming is expected.

A method for drying is not specifically limited in so far as driedpowder or granules can be obtained and, for example, spray drying,fluidized bed drying, freeze-drying or the like can be employed.

The following examples and comparative examples further illustrate thepresent invention in detail but are not to be construed to limit thescope thereof. In the following examples and comparative examples, all"percents" are by weight unless otherwise stated.

EXAMPLES 1-3 and COMPARATIVE EXAMPLES 1-4

Ten times volume of water was added to defatted soybeans and the mixturewas stirred to extract soluble components. Then, the insolublecomponent, "okara", was removed to obtain soymilk. To this was addedhydrochloric acid to adjust to pH 4.5. The precipitated protein wasrecovered and neutralized with sodium hydroxide to obtain a soybeanprotein isolate. This soybean protein isolate was warmed to 30° C. and aprotease preparation (Amano Seiyaku K. K., "Protease B") was addedthereto in an amount of 0.1% per solids content of the soybean protein.Enzymatic hydrolysis was carried out at 30° C. and pH 7.0 for 1 hour.Then, steam was blown into the reaction mixture and the enzyme wasinactivated at 140° C. to obtain an enzymatic hydrolyzed soybean proteinsolution (hydrolysis degree: 10%).

To this enzymatic hydrolyzed soybean protein solution was added soybeanrefined oil in an amount of 10% based on the solids content of thesoybean protein. The mixture was homogenized at pressure of 150 kg/cm²with a homogenizer to obtain an emulsified mixture. To the emulsifiedmixture was added and dispersed an emulsifier (sorbitan trioleate) in anamount of 0.5% based on the solids content of the soybean protein andthe mixture was spray-dried to obtain the desired emulsified soybeanprotein material (Example 1).

At the same time, according to the same manner, the following soybeanprotein materials were obtained except that:

Example 2: no emulsifier was added;

Example 3: the emulsifier was added and the mixture was emulsified;

Comparative Example 1: no enzymatic hydrolysis was carried out;

Comparative Example 2: no enzymatic hydrolysis was carried out, noemulsifier was added and, after addition of soybean refined oil, themixture was emulsified;

Comparative Example 3: only enzymatic hydrolysis was carried out and nosoybean refined oil and emulsifier were added; and

Comparative Example 4: no treatment was carried out, i.e. the soybeanprotein isolate itself.

Each soybean protein material thus obtained (8%), sodium caseinate(0.1%), corn powder (3.5%), whole milk powder (0.5%), skimmed milkpowder (0.5%), seasoning (0.5%) and water (made up the total weight to100%) were mixed and dissolved to prepare soup.

Water dispersibility upon admixing, foaming property, defoaming propertyand quality of the resultant soup were evaluated. The results are shownin Table 1.

                  TABLE 1                                                         ______________________________________                                               Ex. No.      Comp. Ex. No.                                                    1     2      3       1      2   3    4                                 ______________________________________                                        Enzymatic                                                                              Yes     Yes    Yes   --     --  Yes  --                              hydrolysis                                                                    Emulsification                                                                         Yes     Yes    Yes   Yes    Yes --   --                              with oil-and-                                                                 fat ingredient                                                                Emulsifier                                                                             Disp.   --     Emul. Disp.  --  --   --                              Water-disper-                                                                          A       A      A     A      A   E    D                               sibility                                                                      Foaming  A       B      B     B      C   E    D                               Defoaming                                                                              A       C      B     C      D   D    E                               Flavor of                                                                              A       A      A     A      A   B    B                               soup                                                                          Color of A       A      A     A      A   B    B                               soup                                                                          Overall  A       C      B     C      D   E    E                               evaluation                                                                    ______________________________________                                         Yes: carried out, -: not carried out, Disp.: dispersed Emul.:                 emulsification                                                           

The hydrolysis degree is a ratio (%) of 0.22M trichloroaceticacid-soluble protein to the total proteins.

Water-dispersibility, flavor and overall evaluation were evaluated bythe following criteria.

A: very good

B: somewhat good

C: average

D: somewhat bad

E: bad

Foaming was evaluated by the following criteria.

A: slightly foaming

B: somewhat foaming

C: considerably foaming

D: violently foaming

E: Only foam was observed.

Defoaming was evaluated by the following criteria.

A: very good defoaming

B: somewhat good defoaming

C: average

D: somewhat bad defoaming

E: considerably bad defoaming

As seen from the results of Table 3, the most desired effect wasobtained by conducting all of enzymatic hydrolysis, emulsification withthe oil-and-fat ingredient and dispersion of the emulsifier. However,even when the emulsifier was emulsified, the resulting material could beserved for a practical use, though foaming and defoaming were somewhatbad.

EXAMPLES 4 AND COMPARATIVE EXAMPLE 5

According to the same manner as described in Example 1, emulsifiedsoybean protein materials were prepared by changing the amount of theprotease, i.e., 0% (the same as Comparative Example 1), 0.03% (the sameas Example 1), 0.25% and 0.50% (Comparative Example 5).

Each soybean protein material thus obtained (7%), egg white (5%), sodiumcaseinate (5%), salt (2.8%), sodium nitrite (0.02%), sodium L-ascorbate(0.06%), phosphate (0.7%), saccharides (5.0%), seasoning (0.3%), sodiumsuccinate (0.02%), a coloring agent (0.2%) and water (made up the totalweight to 100%) were mixed and dissolved to prepare a pickling solution.

The pickling solution (100 parts by weight) was injected into a rawmaterial meat (a loin of Danish pork) from which a tendon and the likewere removed (100 parts by weight) by an injector and subjected totumbling at 5° C. for 10 to 20 hours with a rotary massage machine. Themeat was filled in a casing and, after heating at 65° C. for 30 minutes,it was dried, smoked at 75° C. for 30 minutes, boiled at 78° C. for 120minutes and cooled to obtain ham.

At this time, foaming and defoaming of the pickling solution and thetissue of the ham thus produced (pool of pickling solution, taste andtexture) were evaluated. The results are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                Comp.   Ex. 4           Ex. 4                                                                              Comp.                                            Ex. 1   No. 4  Ex. 1    No. 5                                                                              Ex. 5                                    ______________________________________                                        Protease  0         0.03   0.1    0.25 0.5                                    Hydrolysis                                                                              4         6      10     20   30                                     degree                                                                        Viscosity D         B      A      A    A                                      Foaming   B         A      A      B    C                                      Defoaming C         A      A      A    B                                      Pool of pickling                                                                        C         B      A      A    A                                      solution                                                                      Taste     A         A      A      A    C                                      Texture   A         A      A      B    D                                      Overall evalua-                                                                         C         B      A      B    C                                      tion                                                                          ______________________________________                                    

Foaming and defoaming were evaluated according to the same criteria asshown in Table 1.

Viscosity was evaluated according to the following criteria.

A: considerably low

B: somewhat low

C: average

D: somewhat high

E: considerably high

A pool of the pickling solution was evaluated according to the followingcriteria.

A: No pool of the pickling solution and no stripe was observed.

B: Only a little pool of the pickling solution and stripes were formedbut almost indistinguishable.

C: Some pools of the pickling solution and stripes were formed but notnoticeable.

D: Pools of the pickling solution and stripes were formed and somewhatnoticeable.

E: Pools of the pickling solution and stripes were formed andconsiderably noticeable.

Texture was evaluated according to the following criteria.

A: Texture was uniform and feeling for chewing was good.

B: Texture was tender.

C: Texture was tender and somewhat brittle.

D: Texture was considerably tender and brittle.

E: Texture was considerably tender, brittle and dry.

As seen from the results of Table 2, the hydrolysis degree of 5 to 20 issuitable. When the hydrolysis degree was lower than this, viscositybecomes high and defoaming became difficult. On the other hand, when thehydrolysis degree was higher than the above, although viscosity wasreduced, foaming upon preparation of the pickling solution was increasedand the texture of ham was deteriorated.

EXAMPLES 5-6 AND COMPARATIVE EXAMPLE 6

According to the same manner as described in Example 1, emulsifiedsoybean protein materials were prepared by changing the amount ofsoybean refined oil, i.e., 0% (Example 5), 5%, 10% (the same as Example1), 25%, 50% and 100% (Comparative Example 6). According the same manneras described above, ham was produced by using each soybean proteinmaterial thus obtained.

At this time, states of the pickling solution and the tissue of the hamthus produced were evaluated. The results are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                                        Ex. 5          Ex. 5   Comp.                                           Ex. 6  No. 6  Ex. 1   No. 7                                                                              No. 8                                                                              Ex. 6                                ______________________________________                                        Amount of  0        5      10    25   50   100                                oil-and-                                                                      fat                                                                           ingredient                                                                    Water-     D        B      A     A    A    A                                  dispersi-                                                                     bility                                                                        Foaming    C        B      A     A    A    A                                  Defoaming  B        A      A     A    A    A                                  Pool of    D        C      A     A    C    D                                  pickling                                                                      solution                                                                      Taste      C        B      A     A    A    A                                  Texture    B        A      A     A    B    D                                  Overall    D        B      A     A    B    D                                  evalua-                                                                       tion                                                                          ______________________________________                                    

Evaluation was carried out according to the same criteria as shown inTables 1 and 2.

As seen from the results of Table 3, although the oil-and-fat ingredientis not added, the texture of ham can be improved with less foaming, theamount of the oil-and-fat ingredient is suitably 5 to 50%. When theamount was smaller than this, water-dispersibility was deteriorated anda pool of the pickling solution was formed. When the amount was largerthan the above, stripes were formed in the ham.

EXAMPLE 7

According to the same manner as described in Example 1, emulsifiedsoybean protein materials were prepared except that soybean refined oil(15%) was added to the soybean protein isolate solution of Example 1,the mixture was emulsified and then enzymatically hydrolyzed withaddition of the protease and the amount of the emulsifier was changed,i.e., 0.05%, 0.1%, 0.5% (the same as Example 1), 1.0%, 3.0% and 5.0%.

By using each material, soup was prepared according to the above 8%formulation and foaming was evaluated upon dissolution and quality ofthe resultant soup were evaluated. The results are shown in Table 4.

                  TABLE 4                                                         ______________________________________                                               No. 9                                                                              No. 10  Ex. 1   No. 11                                                                              No. 12                                                                              No. 13                                ______________________________________                                        Amount of                                                                              0.05   0.10    0.50  1.0   3.0   5.0                                 emulsifier (%)                                                                Foaming  B      B       A     A     A     A                                   Defoaming                                                                              C      A       A     A     A     A                                   Taste    A      A       A     B     C     D                                   Color    A      A       A     A     A     B                                   ______________________________________                                    

As seen from the results of Table 4, the amount of the emulsifier issuitably 0.1 to 3.0%. When the amount was smaller than this, only alittle effect on improvement of foaming and defoaming was expected. Whenthe amount was larger than the above, the flavor of the emulsifierbecame strong and taste became bad. A smaller amount of the emulsifieris more desirable from the view point of the flavor and, whenemulsification was carried out as Example 3, its improvement effect wasreduced and, for obtaining the same effect, a larger amount of theemulsifier was required.

As described hereinabove, the emulsified soybean protein material of thepresent invention is readily dispersed and dissolved upon production ofa pickling solution. And foaming is inhibited upon production andapplication to ham. In addition, viscosity is low and therefore it ispossible to produce a pickling solution having a high concentration andto inject a large amount of the pickling solution. Further, is it has anexcellent gel-forming ability and therefore it is suitable for a soakingsolution of ham. Furthermore, the ham produced by using the picklingsolution has good meat taste without soybean flavor, bright color andhigh commercial value and has good quality without a pool of thepickling solution and stripe. When the material of the present inventionis utilized as a protein source of drinking food and the like, it showsgood dispersion and dissolution as well as good workability because ofless foaming. Further, when it is used for soup, drinking and the like,it shows good dispersion with inhibiting foaming and good taste.

What is claimed is:
 1. A process for producing a soybean proteinmaterial which comprises the steps of: hydrolyzing soybean protein witha protease in an aqueous system to a hydrolysis degree of 5 to 20;emulsifying an oil-and-fat ingredient with soybean protein in an amountof 5 to 50 parts by weight per 100 parts by weight of the soybeanprotein before or after the hydrolysis step; and drying the resultantemulsified mixture.
 2. A process according to claim 1 which furthercomprises a step for addition of an emulsifier.
 3. A process accordingto claim 1, wherein 0.1 to 3 parts by weight of the emulsifier is addedper 100 parts by weight of solids of the soybean protein.
 4. A processaccording to claim 1, wherein the soybean protein material is to be usedfor a pickling solution.
 5. A process for producing a soybean proteinmaterial which comprises the steps of: hydrolyzing soybean protein witha protease in an aqueous system to a hydrolysis degree of 5 to 20;adding an emulsifier and then drying the resulting mixture.
 6. A processaccording to claim 5, wherein 0.1 to 3 parts by weight of the emulsifieris added per 100 parts by weight of solids of the soybean protein.
 7. Aprocess according to claim 1, wherein the soybean protein material is tobe used for a pickling solution.